Fourteen of the 15 anti-spam products tested by Virus Bulletin have been awarded the testing firm's VBSpam award.
The loser was Kaspersky, owing to a quixotic decision by the testers. Kaspersky recorded a very low level of false positives, but missed out on the award because it let through more genuine spam.
Overall, however, the testers declared themselves satisfied with the efficiency of the anti-spam products on the market.
"In the past 10 years, spam has grown from a mere nuisance into a major field of criminal activity, and there are no signs of the problem abating any time soon," said Martijn Grooten, anti-spam test director at Virus Bulletin.
"However, the results of this test demonstrate that anti-spam developers are putting up a strong fight to protect end users' inboxes."
Virus Bulletin named MailMarshal, SpamTitan, Microsoft, Forefront, Symantec's Brightmail and Webroot for their particularly good performances.